Added support to detect changed dired buffers.

(auto-revert-active-p): New.
(auto-revert-list-diff): New.
(auto-revert-dired-file-list): New.
(auto-revert-dired-changed-p): New.
(auto-revert-handler): New.
(auto-revert-active-p): New.
(auto-revert-buffers): Moved logic to
`auto-revert-handler' and `auto-revert-active-p'

1 files changed, 79 insertions, 18 deletions

diff --git a/lisp/autorevert.el b/lisp/autorevert.el
index fac91332a5e..9005a7c4063 100644
--- a/lisp/autorevert.el
+++ b/lisp/autorevert.el
@@ -244,6 +244,82 @@ Use `auto-revert-mode' to revert a particular buffer."
                             'auto-revert-buffers)
           nil)))
 
+(defun auto-revert-active-p ()
+  "Check if auto-revert is active (in current buffer or globally)."
+  (or auto-revert-mode
+      (and
+       global-auto-revert-mode
+       (not global-auto-revert-ignore-buffer)
+       (not (memq major-mode
+                  global-auto-revert-ignore-modes)))))
+
+(defun auto-revert-list-diff (a b)
+  "Check if strings in list A differ from list B."
+  (when (and a b)
+    (setq a (sort a 'string-lessp))
+    (setq b (sort b 'string-lessp))
+    (let (elt1 elt2)
+      (catch 'break
+        (while (and (setq elt1 (and a (pop a)))
+                    (setq elt2 (and b (pop b))))
+          (if (not (string= elt1 elt2))
+              (throw 'break t)))))))
+
+(defun auto-revert-dired-file-list ()
+  "Return list of dired files."
+  (let (list)
+    (save-excursion
+      (goto-char (point-min))
+      (while (not (eobp))
+        (if (setq file (dired-get-filename t t))
+            (push file list))
+        (forward-line 1)))
+    list))
+
+(defun auto-revert-dired-changed-p ()
+  "Check if dired buffer has changed."
+  (when (and (stringp dired-directory)
+             ;;   Exclude remote buffers, would be too slow for user
+             ;;   modem, timeouts, network lag ... all is possible
+             (not (string-match "@" dired-directory))
+             (file-directory-p dired-directory))
+    (let ((files (directory-files dired-directory))
+          (dired (auto-revert-dired-file-list)))
+      (or (not (eq (length files) (length dired)))
+          (auto-revert-list-diff files dired)))))
+
+(defun auto-revert-buffer-p ()
+  "Check if current buffer should be reverted."
+  ;;  Always include dired buffers to list. It would be too expensive
+  ;;  to test the "revert" status here each time timer launches.
+  (or (eq major-mode 'dired-mode)
+      (and (not (buffer-modified-p))
+           (if (buffer-file-name)
+               (and (file-readable-p (buffer-file-name))
+                    (not (verify-visited-file-modtime buf)))
+             (and revert-buffer-function
+                  (or (and global-auto-revert-mode
+                           global-auto-revert-non-file-buffers)
+                      auto-revert-mode))))))
+
+(defun auto-revert-handler ()
+  "Revert current buffer."
+  (let (done)
+    (cond
+     ((eq major-mode 'dired-mode)
+      ;;  Dired includes revert-buffer-function
+      (when (and revert-buffer-function
+                 (auto-revert-dired-changed-p))
+        (setq done t)
+        (revert-buffer t t t)))
+     ((or (buffer-file-name)
+          revert-buffer-function)
+      (setq done t)
+      (revert-buffer 'ignore-auto 'dont-ask 'preserve-modes)))
+    (if (and done
+             auto-revert-verbose)
+        (message "Reverting buffer `%s'." (buffer-name)))))
+
 (defun auto-revert-buffers ()
   "Revert buffers as specified by Auto-Revert and Global Auto-Revert Mode.
 
@@ -294,24 +370,9 @@ the timer when no buffers need to be checked."
                        (memq buf auto-revert-buffer-list))
                   (setq auto-revert-buffer-list
                         (delq buf auto-revert-buffer-list)))
-              (when (and
-                     (or auto-revert-mode
-                         (and
-                          global-auto-revert-mode
-                          (not global-auto-revert-ignore-buffer)
-                          (not (memq major-mode
-                                     global-auto-revert-ignore-modes))))
-                     (not (buffer-modified-p))
-                     (if (buffer-file-name)
-                         (and (file-readable-p (buffer-file-name))
-                              (not (verify-visited-file-modtime buf)))
-                       (and revert-buffer-function
-                            (or (and global-auto-revert-mode
-                                     global-auto-revert-non-file-buffers)
-                                auto-revert-mode))))
-                (if auto-revert-verbose
-                    (message "Reverting buffer `%s'." buf))
-                (revert-buffer 'ignore-auto 'dont-ask 'preserve-modes)
+              (when (and (auto-revert-active-p)
+                         (auto-revert-buffer-p))
+                (auto-revert-handler)
                 ;; `preserve-modes' avoids changing the (minor) modes.  But we
                 ;; do want to reset the mode for VC, so we do it explicitly.
                 (vc-find-file-hook)))